Generic peptide substrate for use in TR-FRET biochemical kinase assays. Refer to Selector Guide for validated kinases. CREBtide peptide (sequence: CKRREILSRRPSYRK) labeled with ULight™ dye. Synthetic peptide derived from human cAMP Response Element Binding (CREB) Protein (phosphorylation site: Ser133). CREB (Ser 133) can be phosphorylated by a variety of kinases including MSK1, PKA and PKC isoforms.